\documentclass{article}

\title{Zermelo-Fraenkel set theory axioms}
\author{Dzmitry Lazerka}

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\begin{document}

Define
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\in
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Define
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Sets
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Axioms:
\begin{enumerate}
\item
Axiom of extensionality
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\forall x \in Sets \forall y \in Sets (\forall z (z \in x
\Leftrightarrow z \in y) \Rightarrow x = y)
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\item
Axiom of regularity
\begin{wikimathdb}{let}
\forall x \in Sets (\exists y (y \in x) \Rightarrow \exists y (y \in
x \wedge \neg \exists z (z \in y \wedge z \in x)))
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\end{enumerate}
\end{document}
